1. Field of the Disclosure
This disclosure relates generally to drill bits and systems for using the same for drilling wellbores.
2. Background of the Art
Oil wells (also referred to as “wellbores” or “boreholes”) are drilled with a drill string that includes a tubular member carrying a drilling assembly (also referred to as a “bottomhole assembly” or “BHA”) having a drill bit attached to the bottom end thereof. The drill bit is rotated by rotating the drill string from a surface location and/or by a drilling motor (also referred to as the “mud motor”) in the BHA to disintegrate the rock formation to drill the wellbore. One type of drill bit, referred to as the PDC bit. A PDC bit typically includes a number of blade profiles. Each blade profile typically includes a cone section, nose section and shoulder section, each such section having a number of cutters thereon. PDC bits are made with different blade profiles and often are categorized as low profile, medium profile and long profile bits. The low profile bits provide a higher rate of penetration and exhibit low stability (i.e., high lateral vibrations) compared to the medium profile bits, while the medium profile bits provide a higher rate of penetration and a lower stability compared to the long profile bits. Often the same bit is used to drill through different formations, such as sand (soft formation) and shale (hard formation), wherein it may be desirable to switch from a short profile bit to a medium profile or long profile bit when transitioning from a soft to hard formation or vice versa.
The disclosure herein provides an improved drill bit that possesses properties more useful for drilling through different formations.